Communities Told to Improve Water Purity

By TESSA MELVIN

Published: January 19, 1992

NEW Federal and state standards for water quality are forcing local officials in Westchester to step up plans for expensive filtration plants or to search for alternative supplies. The mandates are also increasing demands for a regional approach to water management.

Westchester relies on the vast New York City reservoir system for 85 percent of its drinking water. Earlier this month, 11 municipalities in the county learned from state health authorities that their current treatment programs are inadequate and that new proposals to meet strict new standards of water purity must be submitted by March 31.

Communities have until June 1993 to put their plans into effect, seven years after amendments to the Safe Water Drinking Act were passed by Congress in 1986. The Federal law prompted the state to enact even tougher standards, later modified, which originally called for all surface water supplies to be filtered.

Some of the affected Westchester commmunities, like Irvington and Briarcliff, rely exclusively on the Croton Reservoir system, where water quality has steadily deteriorated. Although the Croton supply still meets Federal standards for safe drinking, state authorities are now requiring that every gallon of water be filtered.

Although New York City is building a $600 million water-filtration plant for the Croton Reservoir in the Bronx, that new system will handle only the part of the supply serving New York City residents.

Other Westchester communities, including Harrison and the town and village of Mamaroneck, draw their water from the Rye Lake section of the Kensico Reservoir, which state authorities ordered filtered.

Five other Westchester communities connect to the Catskill Reservoir above the Kensico Reservoir in northern Westchester, where the water, especially in springtime, is unusually muddy. Date With Destiny Delayed

Parts of Yorktown, Montrose, Cortlandt, Pleasantville and New Castle have learned that the increased turbidity in their supply will require them to develop alternatives to meet new water-purity standards or seek another supply.

Other Westchester communities, although escaping their neighbors' fate under the state guidelines released this month, realize that their date with a costly destiny has only been delayed. These communities, which draw their water from the Delaware and Catskill sections of the New York City Water Supply System, are waiting for the outcome of the city's current negotiations with upstate communities to set strict new rules for watershed protection.

The regulations, if enacted, would severely limit residential and commercial development in the 11-county watershed region, but the proposals have encountered bitter local opposition. If political considerations force these proposed regulations to be diluted, state officials have warned that their new regulations governing water purity will take effect.

New York City would then be required to filter the Delaware and Catskill Reservoirs, the largest part of its system, at an estimated construction cost of $6 billion and a yearly maintenance cost estimated at $600 million. The implications are dire, city officials agree. "We get 90 percent of our water from Delaware-Catskill, and protecting the watershed around that system is a crucial economic issue for New York City and the region," said Sanford Evans, deputy commissioner for public affairs with the New York City Department of Environmental Protection. "This is no tree-hugger's fear."

James R. Covey, the associate director of the Bureau of Public Water Supply in the State Health Department, said his department hoped that the city would be better able to protect its remaining watershed area. "The Croton Reservoir is in a highly developed area," Mr. Covey said. "With major interstates and with large development complexes smack dab in the middle of the water supply, you must filter."

New York City still has a chance to avoid the same thing happening in the Delaware-Catskill watershed, Mr. Covey said. "We have required a long-term plan from them showing they have the resources available to meet our requirements. If the city can establish and enforce its criteria for watershed protection, it won't have to filter water from the Delaware-Catskill." New Guidelines Under Consideration

Environmental groups and some state and city officials are concerned that continued development in the Croton watershed will cause the raw water quality of the Croton to deteriorate rapidly, conditions they say are also occurring in other watershed areas. The Hudson Valley region in which the watershed is situated is one of the fastest-growing areas in the state, with planners predicting that by 2015 its population will have grown 20 percent from the 1988 level.

State law allows the discharge of treated sewage into the reservoir system, but the process for obtaining permits allows for many violations, environmental groups charge. Officials who monitor permits for the State Department of Environmental Conservation said the department is considering new guidelines to limit discharges.